According to ancient and medieval science, aether is the material that fills the region of the universe above the terrestrial, or sublunary, sphere. This sphere was the realm of changing nature. Beginning with the Moon, up to the limits of the universe, everything was permanent, regular and unchanging – the region of aether where the planets and stars are located. Only in the sublunary sphere did the powers of physics hold sway. To go "beyond the aether" is a metaphor for transcending the very limits of the all that is known and unknown.
Like a wave in the physical world, in the infinite ocean of the medium which pervades all, so in the world of organisms, in life, an impulse started proceeds onward, at times, may be, with the speed of light, at times, again, so slowly that for ages and ages it seems to stay, passing through processes of a complexity inconceivable to men, but in all its forms, in all its stages, its energy ever and ever integrally present.